Researchers Comment on Proposed EPA Models for Predicting Broiler Operation Emissions

Proposed federal draft models designed to guide emissions forecasting for broiler operations need improvement and clarification, according to an in-depth analysis led by Iowa State University scientists.

In August, the U.S. Environmental Protection Agency released a set of draft models to estimate daily levels of ammonia, hydrogen sulfide and several types of particulate matter (dust) typically emitted from U.S. broiler operations. The original data stemmed from the National Air Emissions Monitoring Study (NAEMS), which measured emissions to eventually guide Clean Air Act policies for livestock and poultry operations. Once finalized, the EPA emissions models may be used by animal feeding operations to determine whether their emissions trigger air quality reporting requirements.

The agency developed the proposed models for broiler operations using environmentally focused datasets collected between 2005-2007 at a small number of broiler houses in California and Kentucky.

“EPA’s models are quite outdated,” said Brett Ramirez, associate professor of agricultural and biosystems engineering at Iowa State, and assistant director of the Egg Industry Center. Ramirez is one of the researchers who evaluated the EPA draft emissions models. “The underlying data set is 15 years old. A lot has changed since then, including the sizes of barns, nutrition, genetics and management practices in facilities.”

“The EPA model development approach is also very complicated,” Ramirez said. “Using the EPA model as it is currently proposed would be beyond the capability of many growers – especially smaller facilities - and might even be less accurate than calculating emissions based on the numbers of birds a facility will house during a specific time period.”

In addition, the EPA model data comes from only four facilities at three sites in Kentucky and California, neither of which are among states that currently produce the most broilers annually. “At the time of NAEMS, there were limited resources and a best effort was made, but it means the results don’t adequately represent today’s industry across the U.S.,” Ramirez said.

Source: iastate.edu

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